Activation in fusiform gyrus is not correlated with face recognition: normal cortical activation with impaired face recognition in congenital prospagnosia

Abstract

Although there is general consensus that specific parts of the ventral temporo-occipital regions are consistently activated in functional imaging studies of face processing, it is still debatable whether this activation is sufficient for face recognition. We have explored this issue in the context of a group of three adults (two of whom are family members) with congenital prosopagnosia in the absence of any discernible cortical lesion. On detailed behavioral testing, relative to matched control subjects, all subjects were impaired on the Benton and van Allen Facial Recognition test, showed significantly slower reaction time on matching faces presented from the same and from different viewpoints, showed a reduced face inversion effect and were impaired at recognizing famous faces, despite normal visual acuity, intact low level visual processing and normal cognition. All subjects were also slower than their controls on tasks of object recognition requiring subordinate categorization. In spite of these marked behavioral impairments, fMRI experiments revealed clear face-related activation in the fusiform gyrus in all prosopagnostic subjects. This activation parallels the pattern observed in normal subjects. We conclude that face-related activation in the fusiform gyrus is not sufficient for face recognition.